Re: basic DLD help?

[Shai Ayal]

Thanks everyone, it works now

Shai

Paul Kienzle wrote:
> Octave doesn't allow in-place modification of arrays.  Instead you need 
> to make a copy and return it.
>
> Use:
>
>     octave_value_list retval;
>     RowVector y(args(0).vector_value());
>     double *py = y.fortran_vec();
>     ...
>     retval(0) = y;
>     return retval;
>
> - Paul
>
> On Jul 14, 2005, at 6:22 AM, Shai Ayal wrote:
>
> > Ah,
> >
> > but what if I do want to change the data ?
> >
> > Shai
> >
> > John W. Eaton wrote:
> >
> > > On 13-Jul-2005, David Bateman wrote:
> > > | Even better would be
> > > | |    const RowVector y(args(0).vector_value());
> > > |    const double *py = y.fortran_vec();
> > > | | since as you say fortran_vec calls make_unique except when 
> > > "const", and | since you aren't altering the data past to the 
> > > function, in this manner | you avoid a copy.
> > > Still better would be
> > >   const RowVector y(args(0).vector_value());
> > >   const double *py = y.data();
> > > because if you are only asking for read-only access, you can use the
> > > const data() method and avoid the call to make_unique().
> > > As I recall, the reason for having different names (fortran_vec and
> > > data) was because it was not possible to overload on const in early
> > > C++ dialects.  Now that it is possible, I suppose we could use just
> > > one name instead of two.
> > > jwe

--
Shai Ayal, Ph.D.
Head of Research
BioControl Medical BCM
3 Geron St.
Yehud 56100
ISRAEL
Tel:  + 972 3 6322 126 ext 223
Fax:  + 972 3 6322 125
email: address@hidden



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